Aust cliff preparation

[CWS]

Hi, I've got a bit of a collection of large blocks from the Aust bone bed and not sure I'm doing the best job prepping them.

 

So far I've been breaking them with a hammer and then acid prepping anything interesting I find with vinegar. The bones are usually fragments because they break when splitting the blocks.

 

How is this material best approached, can anyone give some advice please?

[Randyw]

First off i will admit I’m not familiar with the aust bone beds but If you post pictures of the material we could probably give you a more informed opinion. However in most cases I’ve found a hammer to be the wrong tool. I’ve gotten several fossil for my collection from people who shattered them trying to prep with a hammer….

[CWS]

3 minutes ago, Randyw said:

First off i will admit I’m not familiar with the aust bone beds but If you post pictures of the material we could probably give you a more informed opinion. However in most cases I’ve found a hammer to be the wrong tool. I’ve gotten several fossil for my collection from people who shattered them trying to prep with a hammer….

Hi, I'll do a pic but they're large (some shoe box sized) chunks of a hard material packed with remains. Most don't show anything interesting/identifiable before being broken down a bit by which time the damage is usually done. As an example see below fin spine cross section..

 

 

[Ludwigia]

I agree with Randy. You would need at least an air scribe to do this material justice and release the bones intact from captivity.

[Kane]

Topic moved to Fossil Preparation. 

[Welsh Wizard]

You have three choices; 

 

1. break it with a hammer and shift through for anything interesting

2. slowly break down with acetic acid

3. use pneumatic pens and slowly expose bones and teeth.

 

or a combination of the above. 
 

The blocks have a lot of micro fractures from the distance they drop out of the cliff which doesn’t help if you break with a hammer.

 

I tend to favour 2 but it can be time consuming and hit and miss whether there is anything in the blocks.

 

Another factor is when to stop prepping.

[CWS]

4 minutes ago, Ludwigia said:

I agree with Randy. You would need at least an air scribe to do this material justice and release the bones intact from captivity.

Yeah makes sense, but often there's nothing of interest and the blocks are large and extremely hard. It would take an age and you might find there's nothing particularly interesting. That's why I've been splitting them and then using scribe/acid once I've found something that looks promising. It's a popular collecting spot so I hoped there was a better answer, vinegar works a treat so was thinking maybe something a little stronger and just let them stew..

[CWS]

1 minute ago, Welsh Wizard said:

You have three choices; 

 

1. break it with a hammer and shift through for anything interesting

2. slowly break down with acetic acid

3. use pneumatic pens and slowly expose bones and teeth.

 

or a combination of the above. 
 

The blocks have a lot of micro fractures from the distance they drop out of the cliff which doesn’t help if you break with a hammer.

 

I tend to favour 2 but it can be time consuming and hit and miss whether there is anything in the blocks.

 

Another factor is when to stop prepping.

 

Thank you. Yes I've had good results with vinegar, seems to only be good for a few hours then neutralises a bit. What concentration and Soak time would you use? Do you do cycles of acid/ water/ paraloid and repeat?

 

Also im not too popular when doing indoors due to the smell but guess temps outside would dramatically slow the process.. 

[Randyw]

Or choice number 4 wich is what i use for larger blocks… dremel engraver for faster material removal then air scribe for finishing. I use one with an adjustment knob so i can  adjust the force down for more fractured matrix. A word of caution though if the matrix is too fractured the vibration could open up the fractures. So test it on a waste piece first…

[Welsh Wizard]

24 minutes ago, CWS said:

 

Thank you. Yes I've had good results with vinegar, seems to only be good for a few hours then neutralises a bit. What concentration and Soak time would you use? Do you do cycles of acid/ water/ paraloid and repeat?

 

Also im not too popular when doing indoors due to the smell but guess temps outside would dramatically slow the process.. 

 

You’re welcome.

I don’t have much experience of using acid but you can use paraloid or wax to coat uncovered bone. It is a very slow process and some of the blocks have what I assume are calcium carbonate clasts (white and powdery) which eats up acid.

 

Depends what you’re trying to do. The academics tend to use acid for Aust stuff for doing detailed faunal analysis as they can sift through all the teeth and bone bits. the more concentrated the acid the harder it is to control as it’ll just eat through bone quickly.

 

I suspect you know what you are doing from your post and there is no silver bullet to speed things up.

[CWS]

13 minutes ago, Welsh Wizard said:

 

You’re welcome.

I don’t have much experience of using acid but you can use paraloid or wax to coat uncovered bone. It is a very slow process and some of the blocks have what I assume are calcium carbonate clasts (white and powdery) which eats up acid.

 

Depends what you’re trying to do. The academics tend to use acid for Aust stuff for doing detailed faunal analysis as they can sift through all the teeth and bone bits. the more concentrated the acid the harder it is to control as it’ll just eat through bone quickly.

 

I suspect you know what you are doing from your post and there is no silver bullet to speed things up.

 

Im figuring it out as I go along. So far using small batches doing 8 hours has been ok but the exposed ends of the bone do suffer. I wondered how others approach it so that's good to know.

 

Its cool seeing them exposed, one of the last batch turned out to be a jaw bone with a rooted tooth!

 

 

Edited January 1, 2023 by CWS